Get your taxes done using TurboTax

1.  It’s her earnings, not her AGI which determines her file requirement. All dependent children who earn more than $12,550 of income in 2021 must file a personal income tax return and might owe tax to the IRS.

2.  Yes, to get back tax withheld she has to file a return. 
3.  What was the 1099-misc for?